Re: [patch -mm] net namespace: empty framework

[Kirill Korotaev <dev@sw.ru>]

Cedric,

Dmitry Mishin and Daniel Lezcano are working together on the full
network namespace incorporating both needs of OpenVZ and VServer/IBM.

Thanks,
Kirill

> From: Cedric Le Goater <cedric@legoater.org>
> 
> This patch adds an empty net namespace framework
> 
> Signed-off-by: Cedric Le Goater <cedric@legoater.org>
> ---
>  include/linux/init_task.h     |    2 +
>  include/linux/net_namespace.h |   49 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/nsproxy.h       |    2 +
>  kernel/nsproxy.c              |   12 ++++++++++
>  net/Kconfig                   |    8 ++++++
>  net/core/Makefile             |    2 -
>  net/core/net_namespace.c      |   41 +++++++++++++++++++++++++++++++++++
>  7 files changed, 115 insertions(+), 1 deletion(-)
> 
> Index: 2.6.19-rc5-mm2/include/linux/init_task.h
> ===================================================================
> --- 2.6.19-rc5-mm2.orig/include/linux/init_task.h
> +++ 2.6.19-rc5-mm2/include/linux/init_task.h
> @@ -8,6 +8,7 @@
>  #include <linux/lockdep.h>
>  #include <linux/ipc.h>
>  #include <linux/pid_namespace.h>
> +#include <linux/net_namespace.h>
>  
>  #define INIT_FDTABLE \
>  {							\
> @@ -78,6 +79,7 @@ extern struct nsproxy init_nsproxy;
>  	.id		= 0,						\
>  	.uts_ns		= &init_uts_ns,					\
>  	.mnt_ns		= NULL,						\
> +	INIT_NET_NS(net_ns)						\
>  	INIT_IPC_NS(ipc_ns)						\
>  }
>  
> Index: 2.6.19-rc5-mm2/include/linux/net_namespace.h
> ===================================================================
> --- /dev/null
> +++ 2.6.19-rc5-mm2/include/linux/net_namespace.h
> @@ -0,0 +1,49 @@
> +#ifndef _LINUX_NET_NAMESPACE_H
> +#define _LINUX_NET_NAMESPACE_H
> +
> +#include <linux/kref.h>
> +#include <linux/nsproxy.h>
> +
> +struct net_namespace {
> +	struct kref	kref;
> +};
> +
> +extern struct net_namespace init_net_ns;
> +
> +#ifdef CONFIG_NET_NS
> +
> +#define INIT_NET_NS(net_ns) .net_ns = &init_net_ns,
> +
> +static inline void get_net_ns(struct net_namespace *ns)
> +{
> +	kref_get(&ns->kref);
> +}
> +
> +extern int copy_net_ns(int flags, struct task_struct *tsk);
> +
> +extern void free_net_ns(struct kref *kref);
> +
> +static inline void put_net_ns(struct net_namespace *ns)
> +{
> +	kref_put(&ns->kref, free_net_ns);
> +}
> +
> +#else
> +
> +#define INIT_NET_NS(net_ns)
> +
> +static inline void get_net_ns(struct net_namespace *ns)
> +{
> +}
> +
> +static inline int copy_net_ns(int flags, struct task_struct *tsk)
> +{
> +	return 0;
> +}
> +
> +static inline void put_net_ns(struct net_namespace *ns)
> +{
> +}
> +#endif
> +
> +#endif /* _LINUX_NET_NAMESPACE_H */
> Index: 2.6.19-rc5-mm2/include/linux/nsproxy.h
> ===================================================================
> --- 2.6.19-rc5-mm2.orig/include/linux/nsproxy.h
> +++ 2.6.19-rc5-mm2/include/linux/nsproxy.h
> @@ -10,6 +10,7 @@ struct mnt_namespace;
>  struct uts_namespace;
>  struct ipc_namespace;
>  struct pid_namespace;
> +struct net_namespace;
>  
>  /*
>   * namespaces flags
> @@ -42,6 +43,7 @@ struct nsproxy {
>  	struct ipc_namespace *ipc_ns;
>  	struct mnt_namespace *mnt_ns;
>  	struct pid_namespace *pid_ns;
> +	struct net_namespace *net_ns;
>  
>  	struct hlist_node ns_hash_node;
>  };
> Index: 2.6.19-rc5-mm2/kernel/nsproxy.c
> ===================================================================
> --- 2.6.19-rc5-mm2.orig/kernel/nsproxy.c
> +++ 2.6.19-rc5-mm2/kernel/nsproxy.c
> @@ -20,6 +20,7 @@
>  #include <linux/mnt_namespace.h>
>  #include <linux/utsname.h>
>  #include <linux/pid_namespace.h>
> +#include <linux/net_namespace.h>
>  
>  #define NS_HASH_BITS 		3 /* this might need some configuration */
>  #define NS_HASH_SIZE		(1 << NS_HASH_BITS)
> @@ -89,6 +90,8 @@ struct nsproxy *dup_namespaces(struct ns
>  			get_ipc_ns(ns->ipc_ns);
>  		if (ns->pid_ns)
>  			get_pid_ns(ns->pid_ns);
> +		if (ns->net_ns)
> +			get_net_ns(ns->net_ns);
>  	}
>  
>  	return ns;
> @@ -136,10 +139,17 @@ int copy_namespaces(int flags, struct ta
>  	if (err)
>  		goto out_pid;
>  
> +	err = copy_net_ns(flags, tsk);
> +	if (err)
> +		goto out_net;
> +
>  out:
>  	put_nsproxy(old_ns);
>  	return err;
>  
> +out_net:
> +	if (new_ns->pid_ns)
> +		put_pid_ns(new_ns->pid_ns);
>  out_pid:
>  	if (new_ns->ipc_ns)
>  		put_ipc_ns(new_ns->ipc_ns);
> @@ -165,6 +175,8 @@ static void free_nsproxy(struct nsproxy 
>  		put_ipc_ns(ns->ipc_ns);
>  	if (ns->pid_ns)
>  		put_pid_ns(ns->pid_ns);
> +	if (ns->net_ns)
> +		put_net_ns(ns->net_ns);
>  	kfree(ns);
>  }
>  
> Index: 2.6.19-rc5-mm2/net/core/Makefile
> ===================================================================
> --- 2.6.19-rc5-mm2.orig/net/core/Makefile
> +++ 2.6.19-rc5-mm2/net/core/Makefile
> @@ -3,7 +3,7 @@
>  #
>  
>  obj-y := sock.o request_sock.o skbuff.o iovec.o datagram.o stream.o scm.o \
> -	 gen_stats.o gen_estimator.o
> +	 gen_stats.o gen_estimator.o net_namespace.o
>  
>  obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
>  
> Index: 2.6.19-rc5-mm2/net/core/net_namespace.c
> ===================================================================
> --- /dev/null
> +++ 2.6.19-rc5-mm2/net/core/net_namespace.c
> @@ -0,0 +1,41 @@
> +/*
> + *  This program is free software; you can redistribute it and/or
> + *  modify it under the terms of the GNU General Public License as
> + *  published by the Free Software Foundation, version 2 of the
> + *  License.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/version.h>
> +#include <linux/nsproxy.h>
> +#include <linux/net_namespace.h>
> +
> +struct net_namespace init_net_ns = {
> +	.kref = {
> +		.refcount	= ATOMIC_INIT(2),
> +	},
> +};
> +
> +#ifdef CONFIG_NET_NS
> +
> +int copy_net_ns(int flags, struct task_struct *tsk)
> +{
> +	struct net_namespace *old_ns = tsk->nsproxy->net_ns;
> +	int err = 0;
> +
> +	if (!old_ns)
> +		return 0;
> +
> +	get_net_ns(old_ns);
> +	return err;
> +}
> +
> +void free_net_ns(struct kref *kref)
> +{
> +	struct net_namespace *ns;
> +
> +	ns = container_of(kref, struct net_namespace, kref);
> +	kfree(ns);
> +}
> +
> +#endif /* CONFIG_NET_NS */
> Index: 2.6.19-rc5-mm2/net/Kconfig
> ===================================================================
> --- 2.6.19-rc5-mm2.orig/net/Kconfig
> +++ 2.6.19-rc5-mm2/net/Kconfig
> @@ -67,6 +67,14 @@ source "net/netlabel/Kconfig"
>  
>  endif # if INET
>  
> +config NET_NS
> +	bool "Network Namespaces"
> +	help
> +	  This option enables multiple independent network namespaces,
> +	  each having own network devices, IP addresses, routes, and so on.
> +	  If unsure, answer N.
> +
> +
>  config NETWORK_SECMARK
>  	bool "Security Marking"
>  	help
>